The manufacture of hollow glass articles is a very ancient and well known art. However, the necessity of modern mass production of certain glass articles such as glass containers has created the requirements and has resulted in the design of modern automated glassware forming machines. As in most manufacturing processes, the cost of labor has increased to such an extent that automation to conserve labor has become a desirable and necessary fact of operating modern manufacturing facilities. In the glass forming art, the most widely used machine for the production of blown glass containers is the I.S. machine manufactured by the Hartford Division of Emhart Industries. This basic machine also is manufactured by other glass machinery manufacturers in other parts of the world and an example of such a machine may be found in U.S. Pat. No. 1,911,119 issued to Ingle on May 23, 1933.
In general terms, the process of forming hollow glass articles which is carried out by the above-referred-to machine, comprises the sequential feeding of glass gobs to the plurality of forming sections of the machine and sequentially controlling the performance of each forming section of the machine in order to carry out the sequence of operations necessary to produce the finished glass container. This sequence begins with the forming of the gob by the feeder and the distributing of the gobs to the forming section by the operation of a gob distributor mechanism which is positioned beneath the feeder and above the forming machines. The gobs normally are moved by gravity along tracks in troughs to the various sections of the glass forming machine. The gob feeder will produce that number of gobs which will correspond to the number of cavities that are found on the parison mold side of the forming machines. For example, the I.S. forming machine, when a double gob machine, has two gobs formed simultaneously and severed from the feeder to fall by gravity to the parison mold which will have the two cavities therein at the parison forming station. The parisons which are formed within the parison or blank mold, are formed either by operation of a pressing mechanism or by a blow and blow operation where the glass is blown against the baffle and thereafter counterblown into the shape of the blank mold. Once the parison has been formed in the blank or parison mold, the mold will be opened thus leaving the parison in an inverted position, neck down, and carried by the neck molds which surround the neck of the parison. The parison is transferred by a mechanism termed an "invert arm" which turns through 180.degree. to carry the parisons from the blank or parison forming station to a blow mold station. At the blow mold station, the parisons are normally released to the blow molds which are closed about the parisons and the parisons dangle from the upper edge of the blow molds and the neck rings are opened and moved back toward the parison forming side of the machine. At this time, the blowheads will come into overlying relationship with respect to the parisons carried in the blow molds and the parisons will be expanded into the shape of the molds. After the parisons have been blown into final form, the blow molds are normally opened exposing the completed bottles, still positioned on bottom plates of the molds, and the upper ends of the containers are gripped by a set of take-out tongs which will be moved upwardly and then outwardly to transfer the completed containers from the blow molding station and place the blown ware on a cooling dead plate where cooling air will help set up the bottom of the containers.
Each of the foregoing operations have in the past been under the mechanical operation of a plurality of reciprocating air-operated motors. All of the motors are connected by pipes which have their other ends commonly located at what is termed the "kiss plate" or manifold plate of the I.S. forming machine. This manifold plate, generally speaking, is a horizontally extending, elongated plate with a vertical face through which a plurality of passages corresponding in number to the number of operating motors that are found on the glass forming machine. Typically, there are motors which raise and lower the blowheads, previously mentioned, operate the take-out tong mechanism to carry the finished containers from the blow molds to the cooling dead plate, baffle operating mechanism at the parison forming station, and motors for opening and closing the parison molds and blow molds. Each section of an individual I.S. section machine has all of these individual motors therein. The various motors found on the typical I.S. glass forming machine are controlled, as to their operation, by the timing of the introduction of air to the motors to effectuate the operation in one direction or a return direction. The air used to drive the motors, depending upon the size of the motors, could be either very low pressure, such as 10-15 psi, up to pressures as high as 50 pounds per square inch, this being particularly true for those pieces of mechanism which have fairly large mass and are being moved in a fairly short period of time. The control valves for the air normally were fitted in what was termed a "valve block."
The valve block basically was a casting which would have as many as 21 vertically positioned poppet valves in passages therein, with the poppet valves being mechanically operated through valve lifters, the lifters in turn being operated by buttons carried on the circumference of a rotating drum. The position of the buttons on the drum was adjustable, circumferentially thereof, by the manipulation of a hand tool in the setting up and adjusting that could be carried out by the machine operator. Each of the individual section machines had a drum of its own and its own valve block. This drum and all the other drums in the other sections would normally be driven by a common drive shaft which in turn was driven in time with the initial timing motor positioned near and normally electrically coupled to the feeder. The drive motor for the drum shaft would also be electrically coupled to a transmitter found at the feeder.
The sequential operation of the different elements of the glassware forming machine were thereby controlled by the position of a plurality of cam elements arranged in a corresponding plurality of grooves circumferentially extending on the surface of the timer drum. It is obvious that the timing operation was not considered as very accurate, primarily because the adjustment of the cams was done by hand and it is difficult with a hand adjustment to make the very precise, proper adjustment that would be necessary when trying to fine tune the machine. This positioning of the cams on the timing drum is an inexact procedure at best when the drum is stationary and when the operator first sets up the timing or the operation prior to the first startup, but it would become even more time-consuming and a painstaking task to change the settings of the cams with any degree of accuracy while the drum is rotating. As you might expect, the degree of accuracy is likely no greater than 3.degree. in the full circumference of the drum. The glass forming machine being a machine that is handling a gob of hot glass through a series of manipulations to ultimately produce a bottle is so sensitive to thermal imbalances that once the machine is running, it normally is necessary to keep it in hot glass in order to be assured of a thermally balanced operation. Therefore, the adjustment which are normally carried out after the startup, are done as the drum is rotating. In addition to the difficulty with repositioning the cams, as accurately as possible, by loosening and then retightening a nut, the continuous use of the timing drum and the cams causes mechanical wear of the cam surface or of the follower associated with the valve member, that actually operates the valve when actuated by the cam. Such wear sometimes delays the operation of the valve to a significant degree, resulting in irregularities in the forming operation and the resultant production of ware which is unacceptable or which is not properly formed. Finally, the worn cam surfaces may fail to actuate the cam follower operating the valve.
In an effort to avoid the aforementioned problems, electronic timing systems have been devised and provide electronic circuits and counters with memory for determining the number of degrees of rotation associated with each operation of a glass-ware forming machine to accurately proportion the duration of the operation and the sequence thereof so as to avoid the mechanical failures of the cam members of the very well-known mechanical timing drums.
U.S. Pat. No. 3,762,907 issued to Quinn et al., discloses an electronic control system which controls and maintains the sequence of events constituting the various steps of ware formation with a degree of accuracy unobtainable by the mechanical timing drum.
The sequential timing of the operation of each forming section of the machine, in accordance with the above-mentioned patent, is accomplished by means of a timing pulse generator located on the drive shaft of the machine which generates one pulse for every degree of rotation of the shaft. While the reset pulse generator is also mounted on the drive shaft for generating one pulse for every 360.degree. of rotation of the shaft, in order to reset the control for the beginning of a new cycle of the machine, this control contains electronic circuitry and memories to store sufficient information to carry out in sequence the necessary operation of each section of the machine. By this means, timing of the operation of a function may be ordered by the mere manipulation of a switch or by the advance or retarding of a memory input as opposed to the somewhat cumbersome procedure previously found necessary in the prior art of using a timing drum. The sequential timing pulses and reset pulses which are generated by the pulse generator are taken to a sequence-distributing circuit in order to distribute sequential and reset signals to the plurality of individual forming sections contained in the total machine. The electronic control system, in accordance with this patent, also contains emergency stop means as well as a program stop means for each section of the machine in order to enable the operator to stop the operation of various mechanisms of the machine, either in a program stop where the sequence will finish out the movement of a glass gob through the machine before the stop, or an emergency stop where the machine will stop in a mode that would avoid the possibility of operator injury.
This electronic control system disclosed in U.S. Pat. No. 3,762,907 represents a mere replacement of mechanical timer drum and, in essence, acts in much the same manner as the timing drum, inasmuch as the electronic system provides signals to a series of solenoids which control the operation of the plurality of valves, rather than the mechanical operation of those valves which were accomplished previously by the cams on the drum. While the electronic control system is capable of changing or shifting the timing of relative variables, and it may be easily concluded that relative variables, i.e., timing of operations that are computed as a proportion of the duration of the entire cycle, may be accurately shifted, with the selection of the position of a predetermined number of switches. It may also be concluded that the handling and changing or shifting of absolute values can hardly be accomplished because the system is not equipped to effect such changes and even if it were, there is no way of testing the new times selected by the operator and there is no way of knowing in advance if the time selectors are correct to prevent a cutting down of certain variables that cannot be decreased or lengthened in order to coordinate them for the total duration of the cycle. In other words, if the absolute times selected by the operator are not accurate and proper, then this must be learned the hard way because the mistakes cannot be apparent until the machine begins normal operation and the formed goods are then determined to be defective.
One of the operations which is critical, after the bottles are formed into their final shape and the take-out mechanism has moved the bottles to a dead plate, is the sweeping of the bottles from the dead plates onto the moving conveyor, which moves past all of the sections of the forming machine and the sequence with which the bottles are formed and the timing of the movement of the bottles from their dead plates onto the conveyor is a very critical and important operation. There are delays that are built in automatically and in present day forming machines these sweepout mechanisms which sweep the ware through approximately a 90.degree. arc, when moving the ware from the dead plate onto the conveyor, have to be operated at a very controlled rate so as not to tip the bottles as they are engaged by the sweepout fingers to transfer and move the bottles from the dead plates to the moving conveyor. At present, this operation is carried out primarily through the rotation of a cam at each section, driven by a drive mechanism which is driven in synchronism with the moving conveyor.
In the present invention, however, this sweepout mechanism and the other major moving mechanisms of the forming machine are to be directly coupled to a reversible, electric motor operating under the control of a computer where there is a master computer for the entire machine and individual microprocessors within a section operators control box which are programmed and may be operator-changed so as to be tuned in connection with each of the sections generally, independently of the other sections. There is dependence, however, on each of the micro-processors with the section operators control box being under the control of the main computer and the memory contained therein.